The loading of a large caliber gun has always involved an element of danger. Most large caliber guns are loaded from the breech end of the gun barrel by one or more crewmembers. The ammunition generally includes one or more projectiles followed by one or more propellant charges. As the projectile and propellants are relatively heavy and typically explosive there is always a danger to the crew should they fall out of a gun during the loading cycle.
Typical large caliber guns have an interior barrel diameter that is greatest at the breech opening and then extends up the barrel to form a chamber. At the end of the chamber the diameter decreases at the forcing cone. The end of the forcing cone is the origin of the bore where interior barrel diameter remains constant for the remaining barrel length. Loading a large caliber gun first involves opening a breech block at the breech or aft end of the gun. The projectile is inserted into the chamber and rammed into place. The nose of the projectile is typically rammed past the forcing cone. Ramming of the ammunition into the barrel can be done manually or by mechanical means. Next, the propellant is placed in the breech behind the projectile, rammed into place and the breech is closed.
The loading process is a very dangerous stage in the firing cycle due to existence of unprotected bags of propellant and the live projectile. There is a danger that the projectile may fall out during the ramming cycle, as the barrel muzzle is typically elevated. There is also an inherent danger from the opposing forces that a hit or even a near-miss my shock the projectile out of the barrel while the breech is open. There is need therefore to prevent the ammunition from falling out of the barrel and into a crew area or crew compartment.
This issue has never been directly addressed in the prior art. In U.S. Pat. No. 4,677,894 leaf springs are employed to retain ammunition in the ammunition receiver, before it is transferred into the chamber of the gun. The ammunition is held by the free end of the leaf spring, but the leaf spring does not support the ammunition once the ammunition enters the cartridge chamber.
U.S. Statutory Invention Reg. No. H794 is directed toward a projectile rotating band for the aft end of a projectile. Among its functions, the band serves to retain the projectile in the forcing cone while it is being loaded, due to enhanced elasticity and friction coefficient of the band relative to the gun barrel. Likewise, U.S. Pat. No. 4,552,071 describes a two-piece de-spin obturator positioned at the aft end of a projectile. The obturator comprises a ring body with a wedge shaped cross-section. The friction created by the fit between the projectile and the outer surface of the obturator prevents the projectile from falling backwards into the breech as the gun is elevated to a more vertical position for firing. However, such devices, being located at the aft end of the projectile, do not engage the gun barrel as early as desirable. Moreover, these devices rely on a friction bond with the barrel rather than mechanical locking which is more reliable.
There is a need then for a projectile that will not fall-back during normal operation, or in the event of misfire, system power failure, rammer failure, high shock or hot gun environments. There is accordingly a need for a more reliable and robust device that will ensure stability of the projectile in such conditions.